Sorry, why won't it work? The idea is that as long as you don't know the ID you can't tell which traffic is coming from the same person across whatever time dur

Sorry, why won't it work? The idea is that as long as you don't know the ID you can't tell which traffic is coming from the same person across whatever time duration you choose to bucket at (finer bucketing gives more privacy but also more computation to decode the logs once given the ID). And if I give you x and hash(x, y), this does not tell you what y is (it just lets you very likely confirm y if you have it)